I like to keep a tube of Banamine on hand. It does expire eventually so it will be need to be replaced and kept up-to-date, but in the event you need Banamine NOW (such as a colicing horse) and it's after hours, you want to have one on hand.
Other medications usually aren't as emergency and I can pick up in town or get from the vet.
I've had way too many horse injuries in the past so I have a very good supply of:
-elasticon (so awesome for keeping leg bandages up)
-duct tape (also good for keeping leg bandages up)
-silver sulfadiazine wound ointment
-prouds off wound ointment
-sharp regular scissors and bandaging scissors
-razor blade (good for cutting bandage supplies .... or cleaning up tissue around a wound)
-maxi pads or diapers (work great for large wounds)
-empty large syringes (if I need to force-feed a powder anti-biotic, or something of that nature for a picky eater)
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.